JP2608802B2 - Metal tube cutting method - Google Patents

Description

The present invention relates to a method for cutting a metal tube.

<Industrial application fields> Metal tubes are used in various fields of machinery and the like as circulatory components for flowing gas, liquid, and the like. For example, it is a pipe or the like for circulating a heat medium in a heating device or a cooling device. In particular, an outline of a cooling device will be described. In general, a circulation path of a refrigerant of the device, that is, a so-called refrigerant cycle, is generally constituted by an expansion valve (5), an evaporator (6), a compressor (7), and a condenser (8) as shown in FIG. ), And the metal tube connects these parts, and is used as a pipe (9) for circulating a refrigerant as a component constituting a heat exchanger such as an evaporator (6) and a condenser (8). .

By the way, as described above, the metal tube which is a component of various mechanical devices and the like is naturally cut into various lengths according to the use and purpose of the finished mechanical device and the like. Conventionally, a method using a circular saw has been generally used for cutting the metal tube.

<Problems to be Solved> However, in the conventional method of dividing the metal tube at once by using the circular saw, burrs are inevitably formed on the inner and outer circumferences of the cut surface, and chips are generated. In this way, the metal tube with burrs and chips is
When it is used for a circulation pipe for flowing a liquid, there has been a problem that good circulation cannot be obtained, such as a decrease in the flow passage area due to the presence of burrs and clogging due to chips.
In particular, this problem is extremely significant when used as a refrigerant circulation pipe of the above-described cooling device. That is,
The cooling device generally utilizes the effect of increasing or decreasing the heat energy when a liquid state (e.g., dichlor, methane, etc.) evaporates. However, even in a refrigerant cycle as shown in FIG. When such impurities are contained, the efficiency of exchanging heat energy naturally deteriorates, and the cooling efficiency decreases. Further, the vaporization of the liquid refrigerant is performed in the expansion valve (5), but in this case, the liquid refrigerant sent from the condenser (8) is sprayed at once through a small hole in order to turn it into a low-temperature, low-pressure atomized refrigerant. Take composition. Therefore, if chips are contained in the refrigerant,
The chips may block the hole of the expansion valve (5), which may not only lower the vaporization efficiency but also cause a failure of the entire apparatus.

For this reason, in the conventional cutting of a metal tube, in order to prevent the above-mentioned adverse effects due to burrs and chips, means for preventing burrs (for example, frequently applying cutting oil to this blade) or generating Means for removing burrs and chips (for example, using a wire brush or air blowing)
Has to be performed, and the process is complicated. Further, due to such a process, cost increase is unavoidable, and therefore, there has been a long-felt demand for a method of cutting a metal tube that is simple and does not generate any burrs or chips.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method of cutting a metal tube such that burrs and chips are not generated.

<Means for Solving the Problems> For this reason, in the metal tube cutting method according to the present invention, the metal tube is cut from both sides to the outer periphery thereof, at least to the inner periphery thereof, by cutting means having cutting edges opposed to each other across the metal tube. An uninterrupted cut is formed, and thereafter, a tensile force in the axial direction of the metal tube is applied to one or both sides of the metal tube main body.

Here, the metal tube refers to a metal tube having a hollow portion, and its cross section includes various shapes such as a circle, an ellipse, a quadrangle, and an oval shape. Of course, for example, a hollow tube as shown in FIG. Also includes those in which a pillar portion is formed in the portion.

<Examples> Specific examples of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a cutting device for carrying out the method according to the present invention. In this device, a cut is made at any part of the outer periphery of a metal tube so as not to reach the inner periphery. In this case, the tube body is divided from the cut by the step of fixing one side of the tube body and pulling the other side in the tube axial direction.

Next, the configuration of the device will be described. In FIG.
(1) is a fixed clamp, (2) is a cutting blade, and (3) is a moving clamp.

The fixed clamp (1) is for pressing and fixing the metal tube (4) from its radial direction, and in this embodiment, it is composed of an inner clamp (1a) and an outer clamp (1b).
The inner clamp (1a) directly clamps and fixes the metal tube (4), and is installed so as to sandwich the metal tube (4) from both sides in the radial direction. The outer clamp (1b) is connected via a spring mechanism (1c) to the outside of the inner clamp (1b) in the tube radial direction so as to further sandwich the inner clamp (1a). Therefore, the fixing of the metal tube (4) by the fixing clamp (1) of this embodiment is performed by tightening the outer clamp (1b) via the inner clamp (1a). A cutting blade (2) whose cutting edge is substantially perpendicular to the metal tube (4) is supported by a bolt at the tube axial side end of the outer clamp (1b). Therefore, when the metal tube (4) is fixed or opened by the fixed clamp (1), the cutting blade (2) also moves along with the movement of the outer clamp (1b). When the fixed clamp (1) is released, the distance between the metal tube (4) and the cutting edge of the cutting blade (4) is set at a distance from the metal tube (4) as shown in FIG. The inner clamp (1a) is supported so as to be longer than the distance to the fixing surface, but the spring mechanism (1c) is interposed between the inner clamp (1a) and the outer clamp (1b) as described above. In the fixed state, as shown in FIG. 1 (b), the cutting edge reaches the metal tube (4) sufficiently.

The cutting blade (2) forms a cut in the outer periphery of the metal tube (4) and is supported by the outer clamp (1b) as described above. In this embodiment, the cutting edge is sandwiched between the metal tube (4). Are provided at two locations so as to face each other.

The moving clamp (3) presses and fixes the metal tube (4) from both sides in the radial direction, similarly to the fixed clamp (1), and is installed so as to sandwich the metal tube (4). The fixed clamp (1) is located close to the cutting blade (2) so that the cutting blade (2) and the fixed clamp (1) are located right and left. The movable clamp (3) is configured to be movable in the axial direction of the tube. With this configuration, it is possible to apply a force to the metal tube (4) in the axial direction with the metal tube (4) fixed. There is.

Although not shown, the metal tube (4) is automatically sent out to the cutting device of the present embodiment.

Next, a specific metal tube cutting step of the cutting apparatus having the above-described configuration will be described.

First, the automatically sent metal tube (4) is fixed by the fixed clamp (1) and the moving clamp (3).
As shown in FIGS. 1 (a) and 1 (b), the fixing clamp (1) is fixed by first tightening the outer clamp (1b), and then the metal tube (4) from the radial direction via the inner clamp (1a). This is performed by sandwiching. On this occasion,
As shown in the figure, the cutting blade (2) supported by the outer clamp (1b) moves the cutting edge toward the center of the tube diameter with the movement of the outer clamp (1b). As shown in Figure (b), the metal tube (4) is firmly fixed by the fixed clamp (1), and the cutting blade (2).
Make a cut from both sides to the outer circumference so that it does not reach the inner circumference. These cuts are formed to have various depths and sizes depending on the blade type, the size of the blade, etc., but at least do not reach the inner circumference of the tube in order to completely prevent the projection from being formed on the inner surface of the tube.

Next, as shown in FIG. 1 (c), while the metal tube (4) is fixed by the fixed clamp (1) and the moving clamp (3), the moving clamp (3) is moved in the tube axial direction. It is moved to the opposite side of the fixed clamp (indicated by the arrow in FIG. 1 (b)). Since a cut is formed between the fixed clamp (1) and the moving clamp (3), the metal tube (4) is torn from the cut by the axial pulling force of the moving clamp (3). You will be divided. Since this division is due to the tensile force in the axial direction of the metal tube (4),
Burrs protruding from the inner circumference of the tube do not occur on the cross section.

In the present embodiment, as shown in FIG. 1 (d), the movable clamp (3) with the divided metal tube (4) fixed is moved toward the tube axial direction fixed clamp side to move the metal tube. (3) A step of hitting the cross sections with each other is performed. In this embodiment, since a projection (A) directed in the axial direction as shown in FIG. 4 is formed on a section of the metal tube (3), the section is made smooth. . Therefore, when performing this step, it is necessary to perform it with some acceleration.

Finally, as shown in FIG. 1 (e), both the fixed clamp (1) and the movable clamp (3) are released, which completes all the steps.

As described above, in this embodiment, the metal tube (4) is divided by the tensile force in the tube axial direction.
It can be carried out extremely easily, and there is no possibility that burrs or chips are generated. In particular, in this embodiment, since a step of colliding the cross sections with each other is taken, the cross sections are smooth, and the divided metal tube (4) can be used for all circulatory system parts. .

In the present embodiment, one side of the metal tube (4) is fixed and the other side is pulled in the axial direction to divide the metal tube (4). For example, a configuration in which tensile force is applied from both sides But of course it is good.

<Effects of the Invention> As is clear from the above description, the metal tube cutting method according to the present invention does not generate any burrs or chips at the time of cutting, and the pipe for heat circulation in a heating device or a cooling device. Etc. can be used without any problems. Further, the process is extremely simple, and the cost is very advantageous.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of an apparatus for practicing the present invention. FIG. 1 (a) is an explanatory view showing a state in which a metal tube is released, and FIG. 1 (b) is a diagram in which a cut is made in the metal tube. (C) is an explanatory view showing a state where the metal tube is cut off, and FIG. (D) is an explanatory view showing a state where the divided sections of the metal tube are bumped against each other. e) is an explanatory view showing a state in which all the cutting steps are completed. FIG. 2 is a cross-sectional view of a metal tube having a pillar formed in a hollow portion, FIG. 3 is a schematic diagram showing a refrigerant cycle in a cooling device, and FIG. 4 is a partial cross-section of the metal tube in FIG. FIG. In the figure, (1) is a fixed clamp, (2) is a cutting blade, (3)
Is a moving clamp, (4) is a metal tube, (5) is an expansion valve, (6) is an evaporator, (7) is a compressor, (8) is a condenser, and (9) is a pipe.

Claims (1)

(57) [Claims] 1. A cutting means having cutting edges opposed to each other across a metal tube forms a cut from both sides of the metal tube to the outer periphery thereof, at least not reaching the inner periphery thereof, and thereafter, one or both sides of the metal tube main body. A metal tube cutting method in which a metal tube is cut by applying a tensile force to the metal tube in the axial direction.